The Gordon Conference on Second Messengers and Protein Phosphorylation in June 1992 will concentrate on the role of protein phosphorylation in the control of cellular function. The whole area of protein kinases and phosphatases is moving very rapidly, at the levels of both cell biology and molecular structure. The first crystal structure of a protein kinase catalytic subunit has just been published, and will likely presage a new era in structure-function analysis in the kinase family. The widespread importance of SH2 domains as docking motifs for Tyr(P) is emerging. New advances in the area of growth-factor activated protein kinases (MAP2 kinases, ERK'S) are breaking down the distinction between protein Ser/Thr and protein Tyr kinases. Tyr phosphatases are now an established and fast-growing family and the identification of a Vaccinia phosphatase capable of acting on Tyr(P) and Ser(P) challenges the original Ser/Thr versus Tyr classification. These, and other, components feed into the control of cell growth and division, metabolism, gene expression, indeed virtually all areas of cellular function. The Conference provides a unique and lively forum for the exchange of information, ideas and prospects for future work. Over the last two years, approximately 80% of the participants in the conference presented data either in posters or as speakers. Such active participation by the conferees at all levels, including graduate students, postdoctoral fellows as well as junior and senior investigators, encourages discussion and fosters new interactions. The sessions planned for the 1992 Conference are: 1) Protein kinase structure and substrate recognition; 2) Protein phosphorylation and the cell cycle; 3) Ser/Thr protein phosphatases in cellular regulation; 4) Tyrosine kinases and SH2 domains; 5) Protein kinases in growth and differentiation 6) Tyr Protein phosphatase family; 7) Cyclic nucleotides and G-proteins 8) Signal transduction and gene expression.